Optimizing the design of a pediatric blood pump through orthogonal experimentation.

Background: Pediatric heart failure patients weighing less than 30 kg are prioritized for small axial flow blood pumps due to their smaller body size. This study aims to optimize the blade design of pediatric axial flow blood pumps by conducting orthogonal experiments on blade parameters and integrating hydraulic experiments with hemodynamic numerical simulations, so as to improve the hydraulic performance of pediatric blood pumps while reducing blood damage.

Methods: This study employs a combination of computational fluid dynamics (CFD) and orthogonal experimentation to optimize six key parameters of the impeller blade. The optimal blade parameter model is determined through range analysis. The hydraulic performance of the optimized model is evaluated via in vitro experiments, which provide pressure and flow data. Additionally, hemodynamic performance is assessed using CFD, with key evaluation indices including flow field characteristics, pressure distribution, and shear stress distribution within the axial flow pump.

Results: From an orthogonal experiment, six blade parameters were found to influence blood pump pressure head: the distance between the starting surface of the blade and the hub (W), blade height (h), blade length (L), blade wrapping angle (α), blade outlet angle (β), and blade inlet angle (γ). The approximately linear pressure-flow curve of the optimized axial blood pump meets design requirements at a pump speed of 10000 rpm, achieving a pressure head of 50.8 mmHg and a flow rate of 3L/min. Computational fluid dynamics analysis reveals a smooth flow field with a low maximum reflux rate of 0.16 % in sections I, II, and III. Pressure is evenly distributed, with a maximum of approximately 10Pa in the inner wall of the impeller area, working face of the impeller blade, and guide tail blade. There are no high shear stress areas, with shear stress below 200Pa accounting for approximately 95.08 % and areas exceeding 300Pa accounting for roughly 1.56 %.

Conclusions: This study investigates the correlation between blade parameters and hydraulic performance in axial flow pumps used for blood pumping. The results of both flow field analysis and experimental studies, conducted using orthogonal experiments, demonstrate that the optimized blood pump exhibits enhanced performance in reducing both reflux rate and shear stress. These findings provide valuable insights for the design optimization of pediatric ventricular assist devices.